The present invention generally relates to rotary recording medium reproducing apparatuses capable of placing and leaving a rotary recording medium in a state possible for reproduction within the rotary recording medium reproducing apparatus when a jacket (disc case) having a lid for accommodating the rotary recording medium therein is inserted into and then extracted from within the reproducing apparatus, and also capable of incasing the rotary recording medium within the jacket so that the rotary recording medium can be obtained outside the reproducing apparatus together with the jacket, when an empty jacket is inserted into and then extracted from within the reproducing apparatus. The present invention further and especially relates to the above type of a rotary recording medium reproducing apparatus provided with a disc lifter device for immediately raising and restoring a disc lifter which supports the rotary recording medium above a turntable to a position possible to recover the rotary recording medium, when the disc case is inserted into the reproducing apparatus while the disc lifter is moving down.
Conventionally, in an apparatus for reproducing a rotary recording medium (referring to video disc, PCM audio disc, and the like, and hereinafter simply referred to as a disc), there are types of apparatuses which reproduce a disc when the disc is loaded upon clamping and placing of the disc within the reproducing apparatus, by inserting and then extracting a disc case which has a lid and accommodates a disc therein from within the reproducing apparatus.
As a conventional apparatus of this type, a reproducing apparatus was proposed in a United States patent application Ser. No. 231,868, now U.S. Pat. No. 4,352,174, filed Feb. 5, 1981, entitled "DISC-SHAPED RECORDING MEDIUM REPRODUCING APPARATUS" in which the assignee is the same as that of the present application. This previously proposed reproducing apparatus operates together with a disc case comprising a jacket which has a shape for accommodating a disc and an opening for allowing the disc to go in and out of the jacket, and a lid member inserted through the opening of the jacket for closing the opening of the jacket. The reproducing apparatus comprises an inserting opening through which the case is inserted, a turntable for rotating the disc, clamping means for clamping at least one of the disc and the lid member provided at an innermost part on the opposite side from the inserting opening with respect to the turntable, jacket opening enlarging means provided in the vicinity of the inserting opening, capable of moving over the turntable between a position in the vicinity of the inserting opening and the innermost part of the reproducing apparatus, in response to an operation in which the disc case is inserted into and extracted from the reproducing apparatus, lowering and raising means (disc lifter) for lowering the disc to a position where the disc is placed onto the turntable (position possible to reproduce the disc, and hereinafter referred to as a lowered position) from a clamping position where the disc is clamped by the clamping means upon starting of the reproduction (position possible to support and recover the disc, and hereinafter referred to as a raised position) and raising the disc to the clamping position from the turntable upon finishing or discontinuing of the reproduction, a reproducing transducer for reproducing the disc placed onto the turntable, and moving means for moving the reproducing transducer from a waiting position to a reproducing position with respect to the disc.
In the above proposed reproducing apparatus, the recovery of the disc into the disc case is normally performed when the disc lifter is in the raised position, the disc is supported at the raised position, and an empty disc case is inserted into and then extracted from the reproducing apparatus. On the other hand, if the disc lifter is in the lowered position, the disc will not be recovered into the disc case even when the empty disc case is inserted into and then extracted from the reproducing apparatus. Moreover, in addition to the disc not being recovered, the disc within the reproducing apparatus may be damaged by the insertion and extraction of the disc case.
Accordingly, a reproducing apparatus provided with an erroneous insertion preventing mechanism was proposed in a United States patent application Ser. No. 294,360 filed Aug. 19, 1981, entitled "ROTARY RECORDING MEDIUM REPRODUCING APPARATUS" in which the assignee is the same as that of the present application. In this proposed reproducing apparatus, if the operator erroneously attempts to insert the disc case into the reproducing apparatus when the disc lifter is in the lowered position, the erroneous insertion preventing mechanism prevents the disc case from being inserted when the disc case is inserted halfway into the reproducing apparatus. The erroneous insertion preventing mechanism comprises an angularly rotatable cam operating together with the raising and lowering of the disc lifter, and an erroneous insertion preventing lever which rotates angularly according to the angular rotation of the cam, having one end protruding into a moving path of a pin which moves unitarily with the above jacket opening enlarging means. The above erroneous insertion preventing lever rotates angularly to an operational position while the disc lifter is moving down, to prevent the erroneous insertion of the disc case.
In order to protect the disc and stably carry out the operation, the disc lifter is raised and lowered with a speed which is slow to a certain extent. Hence, it takes approximately two seconds for the disc lifter to move to the lowered position from the raised position. Accordingly, the erroneous insertion preventing mechanism cannot be set to the operational position immediately after the disc lifter starts to move down, and it takes a certain time period before the erroneous insertion preventing mechanism is set to the operational position.
On the other hand, there may be a situation where the operator realizes that the disc is not the disc the operator intended to reproduce, after the reproducing operation is started. In this case, the operator inserts an empty disc case into the reproducing apparatus so as to change the disc. If the empty disc case is inserted into the reproducing apparatus after a certain time period has elapsed from the start of the reproducing operation, no problems will be introduced because the above erroneous insertion preventing mechanism will be at the operational position. However, if an attempt is made to insert the empty disc case immediately after the reproducing operation is started, the empty disc case will be inserted into the reproducing apparatus since the erroneous insertion preventing mechanism will not be set at the operational position in time to prevent the insertion of the empty disc case. When the empty disc case is inserted in this manner, the disc case will scratch the upper surface of the disc which is being lowered. As a result, the signal recording surface on the upper surface of the disc will become damaged. In addition, the disc will not be recovered and will remain within the reproducing apparatus, even when the inserted empty disc case is extracted from the reproducing apparatus.